Exposición al metilmercurio en la población general; toxicocinética; diferencias según el sexo, factores nutricionales y genéticos / Methylmercury exposure in the general population; toxicokinetics; differences by gender, nutritional and genetic factors

El mercurio es un tóxico ambiental que causa numerosos efectos adversos en la salud humana y en los ecosistemas naturales. Los factores que determinan la aparición de efectos adversos y su severidad son entre otros: la forma química del mercurio (elemental, inorgánico, orgánico), la dosis, la edad, la duración de la exposición, la vía de exposición y los factores ambientales, nutricionales y genéticos. En el ciclo acuático del mercurio, una vez que se ha depositado, se transforma en metilmercurio por la acción de determinadas bacterias sulfato reductoras y se bioacumula en los organismos acuáticos incorporándose a la cadena trófica de alimentos. El contenido de metilmercurio es mayor en las especies depredadoras de mayor tamaño y que viven más años como el emperador, pez espada, tiburón, atún o marlín. El metilmercurio se halla unido a las proteínas del pescado por lo que no se elimina mediante la limpieza ni el cocinado del mismo. El feto en desarrollo y los niños pequeños son los más vulnerables a los efectos neurotóxicos del metilmercurio procedente de la ingesta de pescado contaminado. El metilmercurio se absorbe en el tracto gastrointestinal y atraviesa la barrera hematoencefálica y la placenta. Algunos componentes de la dieta como los ácidos grasos poliinsaturados, el selenio, la fibra, los compuestos tiol, algunos fitoquímicos y otros nutrientes pueden modificar la bioaccesibilidad del mercurio y su toxicidad. Además de los factores ambientales, los factores genéticos pueden influir en la toxicidad del mercurio y explicar parte de la vulnerabilidad individual (AU)

Mercury is an environmental toxicant that causes numerous adverse effects on human health and natural ecosystems. The factors that determine the existance of adverse effects, as well as their severity are, among others: the chemical form of mercury (elemental, inorganic, organic), dosis, age, period of exposure, pathways of exposure and environmental, nutritional and genetic factors. In the aquatic cycle of mercury, once it has been deposited, it is transformed into methylmercury due to the action of certain sulphate-reducing bacteria, which bioaccumulates in the aquatic organisms and moves into the food chain. The methylmercury content of large, long-lived fish such as swordfish, shark, tuna or marlin, is higher. Methylmercury binds to protein in fish and is therefore not eliminated by cleaning or cooking the fish. Fetuses and small children are more vulnerable to the neurotoxic effects of methylmercury from the consumption of contaminated fish. Methylmercury is absorbed in the gastrointestinal tract and crosses the blood-brain barrier and the placenta. The intake of certain dietary components such as polyunsaturated fatty acids, selenium, fiber, thiol compounds, certain phytochemicals and other nutrients can modify methylmercury bioaccesibility and its toxicity. Apart from environmental factors, genetic factors can influence mercury toxicity and explain part of the individual vulnerability (AU)

[The estimation of possibilities for the application of the laser capture microdissection technology for the molecular-genetic expert analysis (genotyping) of human chromosomal DNA].

The present study was designed to estimate the possibilities of application of the laser capture microdissection (LCM) technology for the molecular-genetic expert analysis (genotyping) of human chromosomal DNA. The experimental method employed for the purpose was the multiplex multilocus analysis of autosomal DNA polymorphism in the preparations of buccal epitheliocytes obtained by LCM. The key principles of the study were the application of physical methods for contrast enhancement of the micropreparations (such as phase-contrast microscopy and dark-field microscopy) and PCR-compatible cell lysis. Genotyping was carried out with the use of AmpFISTR Minifiler TM PCR Amplification Kits ("Applied Biosynthesis", USA). It was shown that the technique employed in the present study ensures reliable genotyping of human chromosomal DNA in the pooled preparations containing 10-20 dissected diploid cells each. This result fairly well agrees with the calculated sensitivity of the method. A few practical recommendations are offered.

Amplified fragment length polymorphism analysis of Listeria monocytogenes by Experion™ automated microfluidic electrophoresis.

Fifty Listeria monocytogenes strains were genotyped by sAFLP and PCR products were separated by agarose gel and automated chip-based microfluidic electrophoresis. A high congruency of results was observed comparing the two techniques, although for some cultures a better separation of sAFLP fragments was achieved with microfluidic system, which proved to be a highly reliable and reproducible tool to improve the molecular typing of L. monocytogenes, requiring lower volumes of samples and reducing significantly analysis time.

La elevación del colesterol unido a lipoproteínas de alta densidad: perspectiva futura. La CETP como diana terapéutica / Elevation of high-density lipoprotein cholesterol: future perspective. Cholesteryl ester transfer protein as a therapeutic target

La CETP (cholesteryl ester transfer protein) es la proteína responsable de la transferencia de lípidos neutros entre las lipoproteínas. La CETP juega un papel clave en la homeostasis del colesterol, especialmente en la redistribución de colesterol entre partículas y en el transporte reverso de colesterol, por lo que la modificación de su actividad puede modificar el desarrollo y la evolución de la ateromatosis. Los efectos de la inhibición de CETP incluyen: reducción de colesterol LDL y aumento del colesterol HDL y apo A-1, aumento en el tamaño de las partículas LDL y HDL, y reducción del colesterol en las partí- culas ricas en triglicéridos. En consonancia, la inducción de expresión de la actividad CETP en ratones aumenta la susceptibilidad a la aterosclerosis mientras que la inhibición de la actividad CETP en conejos tiende a reducir su desarrollo. Sin embargo, el papel de la inhibición de CETP en la ateromatosis en humanos está todavía por definir (AU)

Cholesteryl ester transfer protein (CETP) facilitates transfer of neutral lipids between lipoprotein classes. CETP plays a key role in cholesterol homeostasis, especially in the redistribution of cholesterol among particles and in reverse cholesterol transport. Consequently, modifying the activity of this protein could influence the development and progression of atheromatosis. The effects of inhibiting CETP include reductions in lowdensity lipoprotein (LDL)-cholesterol and cholesterol in triglyceride-rich particles and increases in high-density lipoprotein (HDL)-cholesterol, apolipoprotein A-1 and the size of LDL and HDL particles. The induction of expression of CETP activity in mice increases susceptibility to atherosclerosis, while inhibition of CETP activity in rabbits tends to reduce its development. However, the role of CETP inhibition in atheromatosis in humans remains to be established (AU)

AFLP-based transcript profiling.

This unit presents an alternative to differential display that allows the quantification of transcripts, based on AFLP-fingerprinting of double-stranded cDNA. The protocol described includes the following steps: the isolation of poly(A)+ RNA from total RNA, the synthesis of double-stranded cDNA, the preparation of template fragments by digestion of the cDNA library with a combination of two restriction enzymes and the ligation of adaptors to the fragment ends, the selective amplification of specific subsets of fragments, and the electrophoretic analysis of these amplification products on standard denaturing polyacrylamide gels. The transcript profiles obtained by this technique are a reliable and efficient tool to identify differentially expressed mRNAs. This unit presents an alternative to differential display that allows the quantification of transcripts, based on AFLP-finger his unit presents an alternative to differential display that allows the quantification of transcripts, based on AFLP-finger.